CSF2 and pulmonary alveolar proteinosis: As the AM is also crucial in alveolar surfactant catabolism (16, 17), ablation of the mice genetic loci for GM-CSF, although does not perturb lung morphogenesis (10), leads to the abnormal deposition of surfactant in the alveolar space, a typical characteristic of pulmonary alveolar proteinosis (16, 20).